Lubricant composition



United States Patent 3,636,002 LUBRICANT COMPOSITION William C. Holmgren, Muskegon, Mich, assignor to American Grease Stick Company, Muskegon, Mich, a limited co-partnership of Michigan No Drawing. Filed Oct. 20, 1958, Ser. No. 768,076 Claims. (Cl. 252-28) The present invention relates to a lubricating composition and is more particularly concerned with a grease type lubricating composition exhibiting high film strength and other useful properties.

In order to be useful as an ideal grease type lubricant, the composition must exhibit high film strength and must retain its lubricating quality and stability over a prolonged period of time. It must have a negligible effect on rubber, synthetic resins and a wide variety of surface coatings, such as lacquer and enamel finishes on automobiles. Further, the lubricant must be operative over a wide temperature range e.g. at 0 Fahrenheit or below and up to a maximum of several hundred degrees Fahrenheit. In addition, repellency to water is a desirable property.

Heretofore, petroleum based greases containing soaps have been used as lubricants, but such compositions readily attack rubber and related materials and are'not effective at temperatures in the order of above 300 Fahrenheit. Water soluble emulsions, such as soaps of the polyglycol type, have been marketed. These are not permanent lubricants and hence cannot be used for lubricating applications where the lubricated parts are in frequent contact with Water or other solvents. As a result, the petroleum oils and greases, and the liquid soap emulsions have not found wide acceptance as lubricants.

In other instances, attempts have been made to utilize castor oil or other non-drying oils for permanent lubricants. Mixtures of castor oil, alcohol and water have been used as liquid soap lubricants for rubber. Upon application, these compositions leave a sticky or tacky residue and upon further drying, the castor oil polymerizes rapidly with the result that the lubricating quality of the composition is readily lost.

More recently, silicone greases havebeen developed and marketed. These possess advantage over other prior art lubricants of improved resistance to water, e.g. Water repellency, high dielectric strength, and offer better per-,

do not possess good wear qualities when lubricating cer-" tain types of materials, such as metals. In addition, be-

cause of their high silicone content, e.g. 50 percent or more by weight, such lubricants are very expensive.

Therefore, an object of the present invention is to provide a grease type lubricant composition exhibiting high film strength and lasting lubricatingqualities.

An additional object of the present invention is to provide an inexpensive grease type lubricant that does not adversely affect rubber, synthetic resins or surface coatmgs.

A further object of the present invention is to provide a composition that embodies drying or non drying oils or oil fatty acids, yet which exhibitsgood oxidation resistance and which retains its stability and lubricity for prolonged periods of time over a wide temperature range.

Still another object of the present invention is to providea grease type lubricant of high film-strength that'contains a silicone material.-

Other objects of the present invention will be apparent to those skilled in this field as the description proceeds.

The present invention' is a grease lubricating composition exhibiting lubricating properties at a temperature of between about minus and about plus 400 Fahrenheit and comprises in its simplest form a compound selected from the group consisting of drying and non-drying oils and oil fatty acids, a synthetic film-forming agent, a thixotropic agent, and an anti-oxidant. In a preferred embodiment, the composition of the present invention also includes a silicone fluid. Other components, such as ultraviolet light absorbers, dispersing agents, and the like, are added where desired.

The compositions of the present invention have utility as lubricants suitable for automotive applications, as for example, in the lubrication of rubber gaskets, weather stripping, hood contact points, fan belts, speedometer cables, brake work, and the like. Such compositions have further utility in the aircraft and related fields for lubrication of aircraft parts.

In the compositions of the present invention, the drying and non-drying oils and oil fatty acids function primarily as film-forming agents. While the non-drying oils, e.g. castor, and oil fatty acids are preferred, the drying oils, e.g. linseed oil, and oil fatty acids are generally operative. Among the non-drying oils useful in the compositions of I the present invention are the castor, peanut, olive, rape and palm oils, which in turn contain such oil fatty acids as ricinoleic, oleic, linoleic, stearic, palmitic, linolenic and mixtures of these acids. Among the drying oils that are generally operative are linseed,perilla, soybean, corn and cottonseed, which in turn contain such fatty acids as linoleic, linolenic, oleic, stearic, palmitic, eleostearic and mixtures thereof. While the primary components of both the non-drying and the dryingoils are the unsaturated fatty acids, the presence of the saturated fatty acids, e.g. stearic, palmitic and the like, in substantial amounts does not detract significantly from the performance of these novel lubricating compositions. While the drying and non-drying oils, as commercially refined and as occasionally dehydrated, as in dehydrated castor oils, are readily available and easily utilized in compositions of the present invention, such pure fatty acids as ricinoleic, linoleic, oleic and the like and mixtures thereof can be employed successfully as the film-forming agent in the compositions of the present invention. However, none 'ofthese agents or combinations can be employed successfully by itself as the sole film-forming component in the compositions of the present invention. Thus, it is desirable to also incorporate a synthetic film-forming agent into the composition; For example,'castor oil at r'educed'temperatures, e.g. 20 F. below zero, tends 'to seed out or'crystallize, thereby losing its lubricating quality. At high tempera ture it tends to polymerize, causing the lubricant to setup, thus also destroying its lubricating value. The use of anti-oxidant compounds with castor oil minimizes only slightly the difiiculties associated with the use of castor oil in conventional grease type lubricants.

Unexpectedly, it has been-found that the non-drying and drying oils and oil fatty acids can be combined with a synthetic film-forming agent, a thixotropic agent, and an anti-oxidant to form a grease type lubricant that meets allthe' essential requirements for performance under widely varying conditions. It has beenfound that the film strength exhibited by the finished lubricating composition is in the order of twice that possessed by castor oil alone or by any of the synthetic film-forming agents per se. This effect, possibly involving'either synergism or a chemical reaction, exerts a strong influence on the performance of the lubricating composition. For example,

film strength data acquired by performance on a standard Falex Lubricant Tester consistently shows film strengths in combination, exhibit film strength values of only 1000 to 1500 pounds. These comparisons are shown in detail under the comparative testing sections following in this specification.

Among the various operative synthetic film-forming agents are the'polyalkylene glycols, such as polyethylene glycol and polypropylene glycol and mixtures thereof.

While the polyalkylene glycol synthetic film-forming a greater temperature range, especially at reduced ternpera-tures, e.g. up to about minus 30 to 40 F. Other synthetic film-formers, such as the parafiin hydrocarbons, including halogenated hydrocarbons, have been incorporated in the novel compositions in relatively small amounts, i.e. in the order of l to 3 percent by weight'of the film forming agents used.

Preferra-bly, the ratio by weight of synthetic film-forming agent to the oil or oil fatty acid film-forming agent is in the order of 2 to 1, although ratios of l to 1 parts by weight have been used successfully. The synthetic'filmforming agents, in addition to lending greater lubricating qualities over a wide temperature range, tend to obviate the undesirable tackiness'exhibited by the oils and oil fatty acids.

Among the thixotropic agents incorporated in the lubricating compositions of the present invention are the silica aerogels. Aerogels having a bulk density of 2.0 to 3.5 pounds per cubic foot and having a relatively small particle size, e.g. 0015-0030 microns, are preferred. Diatomaceous materials, such as diatomaceous earth, and the swelling bentonites, fire clays, kaolin, and the like are operative, especially if the particle size is reduced substantially over that found in the ordinary commercial grades of these materials. The thixotropic agents serve to thicken the composition and control the viscosity of the finished grease lubricating composition. Among the preferred aerogels are Santocel 54 (Monsanto Chemical Company) and Cabosil Fluffy grade (Godfrey L. Cabot, Inc.). While the thixotropic agent serves the function of imparting high temperature resistance and high thickening efiiciency to the grease, it has been found unexpectedly to function with the other preferred components of the compositions of the present invention to yield a grease lubricating composition having superior film strength. The comparative examples demonstrate that film strengths up to a maximum of only about 1600 pounds can be obtained by a combination of the preferred liquid and solid components exclusive of the addition of the thixotropic agent. It is also shown that the addition of the thixotropic agent, e.g. aerogel, to either of the primary film-forming agents alone, i.e. the non drying and drying oils and oil fatty acids, or the polyalkylene glycols, does not enhance the film strength of the resulting composition. However, the addition and proper blending of the thixotropic agent into the predispersion of all the other essential compon ents produces a grease composition exhibiting a marked increase in film strength.

It the thixotropic agent is eliminated from the compositions of the present invention, such compositions at temperatures up to 300 F. become markedly more fluid and tend to volatilize away from the surface being lubricated. Such thixotropic agents thus function to retain the composition as a grease at elevated temperatures.

v The water repellancy of the lubricating greases is improved by the addition of a silicone material such as fluid polydimethylsiloxane and other polydialkylsiloxanes. Other silicone fluids, such as the polyarylalkylsiloxanes, can be (Dow-Corning 200 Series) and polyarylalkylsiloxanes (Dow-Corning 555) for example, having viscosities in this range are preferred. Other silicones, such as Union Carbide and Carbon Company XL42, yield good results. Up to ten percent silicone fluid by weight of the finished composition has been found to produce excellent water repellency. Grease lubricating compositions having as little as 1 percent silicone fluid have successfully passed standard Water washout tests. Grease lubricating compositions of the present invention containing as little as one percent silicone fluid show satisfactory water repellency over a wide range of thermal conditions. The conventional silicone greases, which do possess excellent water repellency, frequently contain in excess of 50 percent silicone fluid by weight and are more costly to produce than the compositions of the present invent-ion. Such commercial silicone greases usually have poor film strengths.

Since non-drying and drying oils and oil fatty acids are important film-forming agents in these novel greases, it is necessary to provide anti-oxidant agents in order to prevent undesirable oxidation from occurring. Such antioxidants as 2,2-methylenebis-(4-methyl-6-tertiarybutyl phenol), 2,5-ditertiarybutyl hydroquinone and tetrachlorohydroquinone are representative anti-oxidants that have been found satisfactory. Amounts up to two to three percent by Weight are sufiicient to control oxidation. The preferred anti-oxidant is 2,2'-methylenebis-(4-methyl-| G-tertiary-butyl phenol).

Ultra-violet light absorbers are included in the novel compositions in order to assure retention of lubricating qualities over prolonged periods of time. In the absence of ultra-violet light absorbers, the selected oil or oil fatty acid tends to polymerize, thus hardening and causing the advantageously employed. Silicone fluids having viscosigrease to lose its lubricating effectiveness. In addition, these absorbing agents help prevent the grease from picking up undesirable colors. Absorbers in amounts of up to about one percent or more by weight of the novel compositions may be incorporated. Usually 0.1-0.2 percent by weight is sufficient. Among the preferred ultraviolet screeners is 2-hydroxy-4-methoxy benzophenone (UV 9).

In preparing the novel compositions, conventional mixing and blending apparatus can be used. It is desirable to admix the liquid components, such as the various filmforming agents, and the solids with relatively low melting points, while heating, and then to add other solids, such as the various anti-oxidants and ultra-violet light screening agents, after the temperature has reached about 200 vF. Thereafter, the aerogel or other thixotropic agent is added at somewhat elevated temperatures e.g. 250300 F. The addition of the thixotropic agent is accomplished best when a shearing effect is applied to the system, as for example, by the use of mixing apparatus having paddles or blades that scrape or otherwise contact the Walls of the mixing container. When aerogel is employed as the thixotropic agent, the elevated temperature tends to drive oif' the residual water present in the aerogel, thus permitting better dispersion to be achieved. If necessary, dispersing agents, such as propylene carbonate, are used to facilitate the blending of the thixotropic agent into the system.

The lubricating grease may then be dispensed in conventional containers, including cans and polyethylene squeeze bottles, or it can be packaged in aerosol or other pressure packaging form. Conventional aerosol propellants, such as trichlorofluoromethane and dichlorodifluoromethane can be used successfully. In such systems, the amount of the lubricating greasefound to give satisfactory results is preferably between about 5 and 20 percent by weight of the aerosol pack. For example, an aerosol package containing 12 percent of the grease composition has been used successfully in commercial practice (Example 11).

The following examples illustrate the methods and compositions of the present invention:

Example 1 Parts by Weight Aerogel (Santocel 54, Monsanto Chemical Company) 15 Castor oil (AA-USP) 72.8 Tricresyl phosphate (TCP) (synthetic film-forming agent) 2-hydroxy-4-methoxy benzophenone (UV 9) 0.2 2,5-ditertiary butyl hydroquinone 2.0

In preparing the composition of Example 1, the castor oil and tricresyl phosphate were admixed and heated to a temperature of about 190 F. The ultra-violet screener (UV 9) and 2,5 ditertiarybutyl hydroquinone were then added and stirring continued, while heating until a homogeneous composition was obtained. The temperature was elevated to about 250 F. and the aerogel blended into the composition in the presence of continued, vigorous shearing agitation.

Following the general mixing procedure for preparation of Example 1, the following Examples 2 to 5, inelusive, were prepared:

Example 2 Parts by weight Aerogel (Santocel 54, Monsanto Chemical Company) 14.0 Castor oil (AA-USP) 74.3 Tricresyl phosphate (TCP) 5.0 2-hydroxy-4-methoxy benzophenone (UV 9) 0.2 2,2'-methylenebis-(4-methyl-6-tertiary-butyl phenol) (AC 5) 0.5 Silicone fluid (Dow-Corning 555) 5.0 Propylene carbon 1.0

Example 3 Aerogel (Santocel 54, Monsanto Chemical Company) 14.0 Castor oil (AA-USP) 73.3 Tricresyl phosphate (TCP) 10.0 2-hydroxy-4-methoxy-benzophenone (UV 9)"--- 0.2 2,2-methylenebis-(4-methyl-6-tertiary-butyl phenol) (AC 5) 0.5 Silicone fluid (Dow-Corning 555) 1.0 Propylene carbonate 1.0

Example 4 Aerogel (Santocel 54, Monsanto Chemical Company) 14.0 Castor oil 74.3 Tricresyl phosphate (TCP) 8.0 2-hydroxy-4-methoxy benzophenone (UV 9) 0.2 2,2'-methylenebis-(4-methyl-6-tertiary-butyl phenol) (AC 5) 0.5 Silicone fluid (Dow-Corning 555) 2.0 Propylene carbonate 1.0

Example 5 Aerogel (Santocel 54, Monsanto Chemical Company) 15.3 Castor il 37.0 Polyalkylene glycol (UCON-LB 385 37.0 Tricresyl phosphate (TCP) 8.0 2-hydroxy-4-methoxy benzophenone (UV 9) 0.2 2,2-methylenebis-(4-methyl-6-tertiary-butyl phenol) (AC 5) 0.5 Silicone fluid (Dow-Corning 555) 1.0 Propylene carbonate 1.0

Example 6 Aerogel (Santocel 54, Monsanto Chemical Company) 14.3 Castor il l 32.0 Polyalkylene glycol (UCON-LB 385) 25.0

Example 6-Continued The castor oil, polyalkylene glycol, polypropylene glycol, beta-chloronaphthalene, tricresyl phosphate and silicone fluid were admixed While heating and agitating until the temperature of the admixture reached about F. Thereafter, the ultra-violet screener and anti-oxidant were added and the stirring continued for ten additional minutes. At that point, the contents of the resulting admixture were transferred to blender apparatus, the temperature raised to 250 F. and the silica aerogel blended slowly into the mixture. The blending in of the aerogel was completed in thirty minutes. The resulting composition was found to be valuable as a grease lubricant.

Following this general mixing procedure, the following compositions of Examples 7 to 9, inclusive were prepared:

Example 7 Parts by weight Aerogel (Santocel 54, Monsanto Chemical Company) 14.3 Castor oil 32.0 Polyalkylene glycol (UCON-LB 385) 24.0 2-hydroxy-4-methoxy benzophenone (UV 9) 0.2 2,2-methylenebis-(4-methyl-6-tertiary-butyl phenol) (AC 5) Silicone fluid (Dow-Corning 555) 1.0 Propylene carbonate 1.0 Polypropylene glycol 25.0 beta-Chloronapthalene (Halowax 4004) 2.0

Example 8 Castor oil 34.1 Polyal-kylene glycol (UCON-LB 385 25.6 Polypropylene glycol 26.6 beta-Chloronaphthalene (Halowax 4004) 2.0 Silicone fluid (Dow-Corning 555) 1.0 2-hydroxy-4-methoxy benzophenone (UV 9) 0.2 2,2'-methylenebis-(4-methyl-6-tertiary-butyl phenol) (AC 5) 0.5 Aerogel (Cabosil flufIy-Godfrey L. Cabot,

Inc.) 10.0

Example 9 Castor oil 34.1 Polyalkylene glycol (UCON-LB 385) 25.6 Polypropylene glycol 26.6 beta-Chloronaphthalene (Halowax 4004) 1.0 Tricresyl phosphate (TCP) 1.0 Silicone fluid (Dow-Corning 555) 1.0 2-hydroxy-4-methoxy benzophenone (UV 9) 0.2 2,2'-methylenebis-(4-methyl-6-tertiary-butyl phenol) (AC 5) 0.5 Aerogel (Cabosil fluffyGodfrey L. Cabot,

Inc.) 10.0

Example 10 Aerogel (Cabosil fluffy-Godfrey L. Cabot, Inc.) 10.0 Castor oil 32.3 Polyalkylene glycol (UCON-LB 385) 25.0 2-hydroxy-4-methoxy benzophenone (UV 9) 0.2 2,2'-methylenebis-(4-methyl-6-tertiary-butyl phenol) (AC 5) 0.5 Silicone fluid (Dow-Corning 555 1.0 Polypropylene glycol 30.0 beta-Chloronaphthalene (Halowax 4004) 1.0 Odor neutralizer (Hello) ml 10.0

oil, polyalkylene glycol, beta-Chloronaphthalene, polypropylene glycol, and silicone fluid were admixed while heating at 230 F. Thereafter, the ultra-violet screener and anti-oxidant were successively added and stirred into the admixture until these components were dissolved therein. To the resulting admixture was blended in slowly the aerogel accompanied by continual agitation and heating.

The blending in of the aerogel took approximately five minutes and the heating at 230 F. and agitation were continued for approximately thirty minutes, at which point the product assumed a shiny, wet appearance. Ten milliliters of Helio were then added to neutralize the odor.

Example 11 (Aerosol package) Pflcem Formulation of Example 10 12.0 'Irichlorofluoromethaue (Freon 11) 53.0 Dichlorodifluoromethane (Freon 12) 35.0

The formulationof Example 10 was packaged in aerosol containers utilizing the above ratio of. components by weight.

Example 12 2,2'-Methylenebis-(4-methyl-6-tertiary-butyl phenol) (AC Aerogel (Cabosil fluify-Godfrey L. Cabot, Inc.).. 10.0

The composition of Example 12, and of the following Examples 13 and 14-was prepared in the manner of Example 7.

Example 13 Castor oil 32.3 Polyalkylene glycol (UCON-LB 385) 25.0 Polypropylene glycol 29.0 beta-Chloronaphthalene (Halowax 4004) 1.0 Tricrcsyl phosphate (TCP) 1.0 Silicone fluid (Dow-Corning 555) 1.0 2-hydroxy-4-methoxy benzophenone (UV 9) 0.2 2,2-methyleuebis-(4-methyl-6-tertiary-butyl phenol) (AC 5) 0,5 Aerogel (Cabosil fluffy-Godfrey L. Cabot, Inc.) 10.0

Example 14 Linseed oil (Commercial grade) 32.3 Polyalkylene glycol (UCON-LB 385) 25.0 Polypropylene glycol 30.0 Silicone fluid (Dow-Corning 555) 1.0

2,2'-methylenebis-(4-methyl-6-tertiary-butyl phenol) (AC 5) 0.5 2-hydroxy-4-methoxy benzophenone 0.2 beta-Chloronaphthalene (Halowax 4004) 1.0

Aerogel (Cabosil"fluify-Godrey L. Cabot, Inc.)- 10.0

use, but without a good film strength value, the composition will not function properly as a lubricant when in contact with a variety of materials. Where metal to metal applications are required, lubricants without high film strength usually fail to give satisfactory performance. The compositions of the present invention function equally well on a wide variety of applications involving metal,

synthetic and natural rubber, paint, lacquer, and resin surface coatings. The commercially available silicone type lubricants do not possess such a Wide diversity of applications. The various test data demonstrating the unusual lubricating qualities ofithe compositions of the present invention are shown in the following section:

A. FILM STRENGTH TEST This test is performed on'a standard Falex Lubricant Tester (Faville-LeValley Corporation). In this test a new set of test pieces is used for each test run. One set of test pieces consists of two Falex V blocks of steel, one Falex No. 8 steel test pin and brass shear pin. The test pin and the V blocks are well lubricated with the product being tested. As the test pin is rotated at 300 r.p.-m., a constantly increasing load is automatically applied through jaws which hold the V blocks against the test pin in a squeezing action. When the lubricant fails, seizure occurs and the shear pin breaks. A gauge records the jaw load at point of failure. At least three tests are run on each product and the results averaged and expressed in pounds of jaw load.

This test measures the over-all lubricating properties of the composition. The greater the test value for film strength, the greater is the field of use for the lubricant. Thus, high film strength lubricants can be used in such mechanical applications as brake work, distributor cams, and speedometer cables, Where continually moving parts are involved.

Employing the standard Falex testing procedure, the following film strength values were obtained for the compositions of the present invention and for the leading competitive products, a value of about 1000-1100 pounds being heretofore generally regarded as good film strength:

Average (1) Compositions of Present Film Strength Film Invention Readings (in pounds) Strength (in pounds) Example 1 1,150, 1,350, 1,450.--. 1, 310 Example 2 1,550, 1,250, 1,800 1, 530 Example 3 0, 2,500, 2,450 2, 310 1,950, 1,600, 1,700---- 1, 720 Example 5-. 2,750, 3,000, 3,100. 2, 970 Example 6 2,400, 2,800, 2,450.... 2, 550 Example 2,750, 3,200, 2,500.--- 2, 625 Example 8.- 2,500, 2,900, 2,800.... 733 Example 9 2,550, 2,500, 2,400.-" 2, 483 Example 10- 2,250, 2,800, 2,650-- 2, 590 2,250, 2,500, 2,150 2,300 2, 533 2, 633 2, 160

It is to be noted that thecompositions of Examples 1 to 4, inclusive, exhibited, on the average, film strengths less than the average of Examples '5 to 14-, inclusive. In the first group of examples an organic phosphate composition was utilized as the synthetic film-forming agent (Tricresyl phosphate). While these synthetic filmforming components are generally operative,-it is also seen from the compositions of the Examples 4 to 14, inclusive, that the polyalkylene glycol type synthetic filmforming agents are preferred.

Average (2) Competitive Compositions Film Strength Film Readings (in pounds) Strengtl1 (in pounds) Competitive Product No. 1 (Dow- 600, 600, 550 550 Coming DC 4X Silicone grease containing aerogel). Competitive Product No. 2 (K-2 1,825, 1,750, 1,650.--- 1, 775 Silicone grease). Competitive Product No. 3 (B-K 1,050, 1,250, 1,170.-. 1,125

m Silicone grease). Competitive Product No. 4 (Y 1712- 700, 750, 650 700 Union Carbide Company Silicone Emulsion). Competitive Product No. 5 (Lubri- 1,100, 1,100, 1,000..-- 1, 060

plate Petroleum base-soap grease). Compotltive Product No. 6 (Stano- 1,150 1,000, 1,250-.-- 1, 133

bar S Petroleum base-soap grease.

(3) Individual Components or Cornbinations of Components Employed in Compositions of the Present Invention Average Film Strength (in pounds) Film Strength Readings (in pounds) 1. Castor Oil o 1, 350

... Castor il Heated to 250 F. and cooled to room temperature. Polypropylene Glycol (M. wt.

. Castor Oil-32 parts Polypropylene glycol-30 parts Castor Oil'32 parts Polypropylene glycol-30 parts Mixture heated to 250 F. and

cooled to 170 F. 6. Pglzgalkylene glycol UCON-LB Castor Oil32 parts Polyalkylenc glycol (UCON- LB 38525 parts). Mixture heated to 250 F. and Ccotolerbti) 170 F. as or 1 Silica aerogel (Cabosil) i L400 Castor Oil was heated to 250 F.,

aerogel added to give consistency equivalent to composition of Example 10 (penetration of 280-350 mm. at 70 F.), and the composition cooled to Croom teinperatuie. 9. astor Oi 32 par s beta-Chloronaphthalene-l.Opart. i 11250 10. Castor Oil-32 parts 2-Hydroxy-4-methoxy benzophe- 1,650, 1,750, 1,550.";

none (UV 9)0.2 part. Mixture heated to 260 F. and

cooled to 180 F. 11. Castor Oil32 parts 2-Hydroxy-4-rneth oxy benzophenone (UV 9)0.2 part. 2,2 Methylenebis- (4-methy1-6- tertiary-butyl phenol)0.5

part. Mixture heated to 250 F. and

cooled to 180 F. 12. Castor Oil-32 parts Polypropylene glycol30 parts 1,400, 1,500, 1,400.. beta-Chloronaphthalene 1.0 part- 13. Castor Oil32 parts Polyalkylene glycol (UCON- LB 385)25 parts. 2,2 -Methylenebis- (4 -methyl-6- tertiary butyl phenol) (AC5)- 05 part. betaECh1oronaphthalene1.0

par Polypropylene glycol-30 parts... Silicone fluid (DC 555)-1.0 part Heated castor oil and polyalkylene glycol to 250 F., added anti-oxidant until dis solved, added remaining components, and cooled to room temperature. 14. Castor Oil-32 parts- Polypropylene glycol pa 2, 2- Methylenebis- (4 -methyl-6- tertiaiy-butyl phenol) (AC5) 0.5 part. Polyalkylene glycol (UCON- LB 385)-25 parts. beta-Chloronaphthalene--1.0

part. Silicone fluid (D C 555)-1.0 part- Heated castor oil and polypropylene glycol to 250 F., added anti-oxidant until dissolved, added remaining components, and cooled to room temperature. 15. Silicone fluid (DC 555) These data show the clear film strength superiority of the compositions of the present invention over the average competitive product.

It is also seen from these data that the unusually high film strength of the novel compositions is not due to any 0 formance.

10 individual component or combination of components tested above in section (3), but rather results from the fortuitous selection of the essential combination of materials, as shown in the examples. None of the individual liquid components alone, or in combination, of the novel compositions exhibit a film strength of greater than about 1 500 pounds. This indicates that the unexpectedly high film strengths are not due to the additive efiect of the components but rather to some unknown phenomenon more closely associated with synergism or with possible chemical reactivity in the system. The unsaturated fatty acids, components in both the drying and non-drying oils, are known to be quite reactive, as are certain of the polyalkylene glycol materials employed as the synthetic filmforming agents.

The compositions of the present invention satisfactorily meet the other properties required for a good grease type lubricant. Since in prior attempts castor oil and other non-drying oils and oil fatty acids failed to possess satisfactory stability upon aging, the novel compositions have been examined carefully for evidences of the formation of undesirable oxidation upon standing. The standard Norma-Hoffman Oxygen Bomb test has been employed, in which a drop in pressure indicates absorption of oxygen by the lubricant and thus a drop in the relative stability of such lubricant. Two hundred hours of testing in the oxygen bomb are regarded as equivalent to two years in service under average conditions, with a drop of ten percent or less in pressure being considered excellent per- Data for representative compositions taken from the Examples are reported below:

Composition: Percent Pressure Drop Example 3 1 i 8.2 Example 5 4.5 Example 6- 9.0 Example 7 9.0 Example 10 9.0 Example 12 9.0

Percent In Compositions Type of crease in Rubber Weight and/0r Volume Natural.-- less than 10.0. Butyl 1.0.

Buna. less than 10.0.

A ten percent increase in volume and/ or weight is regarded as being within the maximum safe limit for a successful lubricant.

Testing of the eliect of the novel lubricant on test panels finished with automobile laquer, enamels and other surface coatings, even with the aerosol packaged novel lubricant products, shows no undesirable action.

Another reason for the prior failure of petroleum oil and castor oil based grease lubricants has been their inability to produce lubrication at sub-zero temperatures. However, the compositions of the present invention when subjected to penetrometer testing under extreme cold conditions gave good lubricating performance at minus 20- 30 F. Heretofore, only silicone type lubricants containing amounts of silicone in the order of 50 percent or more have given satisfactory lubrication in this range.

Likewise, at temperatures in the order of about plus scope of the appended claims.

'from'the spirit or the scope thereof audit is to be understood that such modifications are included within the I claim:

1. A grease lubricating composition exhibiting high film strength lubricating properties at a temperature of eating agent selected from the group consisting of polyalkylene glycols and organic phosphates, the ratio by weight of (b) to (a) being between about 1 to 1 and about in said liquid lubricating agent is a mixture of polyethylene glycol and polypropylene glycol.

I between about minus 30 and about plus 400 Fahrenheit and comprising: (a)'a glycen'de oil; (b) a liquid lubri- 5. The grease lubricating composition of claim 1 wherein said siliceous material is a silica aerogel. l 6. A grease lubricating composition exhibiting high film strength lubricating properties at a temperature of between about minus and about plus 400 Fahrenheit and comprising: (a) a glycen'de oil; (b) a liquid lubricating agent selected from the group consisting of polyalkylene glycols and organic phosphates, the ratio by weight of (b) to (a) being between about 1 to 1 and about 2 to '1; (c) a finely divided inorganic siliceous material in an amount and of a character sufficient to form a thixotropic gel; (d)

an'anti-oxidant; and (e) a silicone fluid.

7. The grease lubricating composition of claim 6 wherein said silicone fluid is present in an amount of between about 0.5 and about 10.0 percent by weight of said composition. i

12 8. A grease lubricating composition exhibiting high film strength lubricating properties at a temperature of between about minus 30 and about plus 400 Fahrenheit and comprising: (a) a glyceride oil; (15) a liquid lubricating agent selected from the group consisting of polyalkylene glycols and organic phosphates, the ratio by weight of (b) to (a) being between about 1 to 1 and about 2 to 1; (c) a finely divided inorganic siliceous material in an amount and of a character sufiicient to form a thixotropic gel; (d) an anti-oxidant; (e) a silicone fluid; and (J) an ultra-violet light absorber. a

9. A grease lubricating composition exhibiting high film strength lubricating properties at a temperature of between about minus 30 and about plus 400 Fahrenheit and comprising: (a) castor oil; (12) polypropylene glycol, the ratio by weight of (b) to (a) being between about 1 to 1 and about 2 to 1; (c) silica aerogel; and (d) an anti-oxidant.

'10. The method of preparing a grease lubricating composition comprising: admixing (a) a glyceride oil and (b) a liquid lubricating agent selected from the group consisting of polyalkylene glycols and organic phosphates, the ratio by weight of (b) to (a) being between about 1 to 1 and about 2 to 1; heating the resulting admixture and adding an anti-oxidant thereto when the temperature of the admixture is about 200 Fahrenheit; and heating the resulting composition to a temperature of between about 250 and about 300 Fahrenheit while adding a finely divided inorganic siliceous material in an amount and of a character sufficient to form a thixotropic gel.

References Cited in the file of this patent UNITED STATES PATENTS 2,412,929 Bogart et a1. Dec. 17, 1946 2,652,361 Woods et al. Sept. 15, 1953 2,677,658 Bidaud May 4, 1954 2,714,091 Puddington et al July 26, 1955 FOREIGN PATENTS 704,604 Great Britain Feb. 22, 1954 

1. A GREASE LUBRICATING COMPOSITION EXHIBITING HIGH FILM STRENGTH LUBRICATING PROPERTILES AT A TEMPERATRUE OF BETWEEN ABOUT MINUS 30 AND ABOUT PLUS 400* FAHRENHEIT AND COMPRISING: (A) A GLYCERIDE OIL; (B) A LIQUID LUBRICATILNG AGENT SELECTED FROM THE GROUP CONSISTING OF POLYALKYLENE GLYCOLS AND ORGANIC PHOSPHATES, THE RATIO BY WEIGHT OF (B) TO (A) BEING BETWEEN ABOUT 1 TO 1 AND ABOUT 2 TO 1; (C) A FINELY DIVIDED INORGANIC SILICEOUS MATERIAL IN AN AMOUNT AND OF A CHARACTER SUFFICIENT TO FORM A THIXOTROPIC GEL; AND (D) AN ANTI-OXIDANT. 